Sulphide impression material



Patented Mar. 26, 1946 UNITED STATES PATENT OFFICE SULPHIDE IMPRESSION MATERIAL Eugene J. Molnar, Toledo, Ohio No Drawing. Application December. 11, 1943,

7 Serial No. 513,993

10 Claims. (CI. 18-47) This invention relates to material for taking Emmille 2 exact impressions of structures with a-view to a Parts reproducing them in plaster or otherwise. It is C ci m c te a 20 an object of the invention to provide a, cheap 31- agneslum oxide 3 gin composition which sets quickly and without 15 Potassium 8 3 the use of heat to a tough strong condition sostmntium sulphide 3 that when applied as an aqueous paste to a struc- Tupi-P55511111! Phosphate ture to be reproduced (such as artwork and fig- Example 3 ures, sculptors work, mechanical shapes and the Parts like, where elastic and plastic properties are of Magnesium arbonat 5 importance), and allowed to harden it can be P wdered mica" 5 stripped intact even when undercuts are present. Powdered a b t 5 I hav found that the sulphides of calcium and sodium alginate 3 strontium when added to a solution of a water- Calcium sulphidp N 3 soluble alginate have the property of causing the Trisodium phosp 0.5

composition to set in a very short time to a tough v strong gel. 'The strength of this gel is considerably greater than is the cas when an alginate composition is set by means of such previously used agents as calcium sulphate, etc. An impression is produced in perfect detail which can be used as a mold to produce a plaster or other type of model.

The composition comprises a dry powder which is mixed with a definite amount of water immediately before use. The powder contains a, wator-soluble alginate (sodium, potassium or ammonium) a filler, and calcium or strontium sulphide or mixtures thereof as the setting agent for the-alginate. The materials used as fillers (magnesium carbonate, calcium carbonate, asbestos, clays, zinc oxide, magnesium oxide, mica, etc.)

make up the bulk of the powder and have some I Example 1 1 Parts Magnesium carbonate 12 Zinc oxide v 3' Sodium alginai'e .3 Strontium sulphide 3 Trisodium phosphate 0.5

The water-powder ratio for the. above examples to make a satisfactory paste is 4 parts water to 1 part powder by weight. -The mixing time is about 1 minute and the setting time about 3 minutes. Th gelled composition in each case is strong, elastic and tough.

To improve the model it is preferable to place the impression in a tanning solution (potassium sulphate, copper sulphate, manganese sulphate,

aluminum sulphate, etc.) which makes possible a faster separation of the impression from the plaster or. artificial stone model and gives a better surface to the model.

I claim:

1. Impression material comprising a water-soluble alginate and a setting agent therefor selected from the group consisting of calcium and strontium sulphide. 1

2. Impression material comprising a water-soluble alginate, a powdered filler, and a setting agent selected from the group consisting of caltherefor selected from the group consisting of calcium and strontium sulphides.

'i. Impression material comprising a water-soluble alginate, a setting agent therefor selected from the group consisting of calcium and strontium sulphides, and a retarding agent.

8. Impression material com a water soiuble elte. a setting agent therefor selected from the group co of calcium and strontium sulphides, a powdered filler, and aretarding agenit/ 9. Impression material comp sodium a1- ginate, a setting agent therefor selected item the group consisting of calcium and strontium ace-zine sulphides, and a soluble phosphate as a retarding agent. r

m t rial comp fl 5w tee, a setting agent therefor selected from the group consisting oi. calcium and strontium sulphides, and a soluble phosphate as a retarding agent.

EUGENE J. MOLNAR. 

